Objective: Drug resistance is a common cause of poor outcome for patients with non-small cell lung cancer (NSCLC) undergoing chemotherapy. Increased excision repair cross-complementation group 1 (ERCC1) and beta-tubulin class III expression have been shown to be associated with resistance to cisplatin and paclitaxel in NSCLC patients, respectively. Epithelial-mesenchymal transition (EMT) has recently been reported to be associated with resistance to chemotherapeutic agents. Snail is a main EMT regulator inducing EMT through the repression of E-cadherin expression. The aim of the study is to investigate the relationship of Snail expression with ERCC1 expression in cisplatin resistance and the relationship of Snail expression with beta-tubulin class III expression in paclitaxel resistance in lung cancer cells. Materials and methods: The human lung cancer cell line H1299 was used for the study. The H1299-Snail-si cell lines were generated by transfecting the pSUPER-Snaili plasmid into H1299 cells. The H1299-Snail-si-ERCC1 and H1299-Snail-si-beta-tubulin class III cell lines were generated by transfecting the pcDNA3-ERCC1 and pcDNA3-beta tubulin class III plasmids into H1299-Snail-si cells, respectively. To evaluate the mRNA expression of Snail, ERCC1 and beta-tubulin class III in different cell lines, quantitative real-time polymerase chain reaction (PCR) was performed. The protein expressions from cell lines were examined by Western blot analysis. All cell lines were treated with various concentrations of cisplatin and paclitaxel for 48 hours, respectively. Cell viability was determined by alamarBlue®, using the natural reducing power of living cells to convert resazurin to resorufin, a fluorescent molecule. Results: The decreased mRNA expression of Snail, ERCC1 and beta-tubulin class III was identified in H1299-Snail-si cells as compared with H1299 cells by PCR and real-time PCR. In H1299-Snail-si cells, ERCC1 protein expression was decreased. H1299-Snail-si cells showed more chemo-sensitivity to cisplatin than H1299 cells. As compared with H1299-Snail-si cells, H1299-Snail-si-ERCC1 cells were more resistant to cisplatin. In H1299-Snail-si cells, beta-tubulin class III protein expression was decreased. H1299-Snail-si cells showed more chemo-sensitivity to paclitaxel than H1299 cells. As compared with H1299-Snail-si cells, H1299-Snail-si-beta-tubulin class III cells were more resistant to paclitaxel. Conclusions: Snail expression was associated with cisplatin and paclitaxel resistance in lung cancer cells. Knockdown of Snail lead to more chemosensitivity to cisplatin and paclitaxel. Re-expression of ERCC1 and beta-tubulin class III in H1299-Snail-si cells lead to more resistance to cisplatin and paclitaxel, respectively. The mechanism of Snail regulating ERCC1 and beta-tubulin class III needs further elucidation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 790. doi:1538-7445.AM2012-790